Without an eve or evening; lacking the period before an event; happening unexpectedly without a preceding night or wait.
From 'eve' + '-less' suffix (without). The '-less' suffix creates opposites in English, as in 'homeless,' 'helpless,' and 'harmless.'
English's '-less' suffix is so powerful that you can add it to almost any noun and instantly create an adjective meaning 'without that thing'—which is why medieval writers could describe sudden, shocking events as 'eveless.'
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